1. Technical Field
This invention relates in general to integrated lead suspensions for hard disk drives and in particular to fabricating and applying non-homogenous laminate materials to an integrated lead suspension with vibration dampening.
2. Background Art
In hard disk drive manufacturing, one type of head gimbal assembly has an integrated lead suspension (ILS). An ILS is typically formed by laminating several layers of material together and then selectively etching the layers to achieve a desired architecture. Alternatively, the layers may be formed by plating them on top of one another. These layers usually comprise at least one of each of the following: a stainless steel substrate or support layer, an insulation layer such as a polyimide, and a conductor layer such as copper. An ILS with a bent lead type design must be etched on both sides to clear the polyimide on the bent lead. This step requires additional process time and adds cost to the suspension.
Uncontrolled vibration in a suspension can limit the performance of a disk drive. Most often, it is desirable to be able to dampen a mode of vibration on a suspension in order to improve the performance. Conventional dampers are available for such purposes, but they are formed from metal and constraint layers in separate processes. Moreover, conventional dampers must be assembled onto the suspension. These additional steps add cost and increase the mass moment of inertia of the suspension. Improved methods for manufacturing integrated lead suspensions are needed to address these issues.
An integrated lead suspension is formed from a five layer laminate of stainless steel, polyimide and copper. Prior to lamination, the steel layer has preformed voids which may have various configurations. The voids are provided for intentionally weakening high strain flexure areas in the suspension so that strain energy can be dissipated more effectively.